Saw testing device



Jan. 21, 1941. BRANTLEY 2,229,548

s aw TESTING DEVICE Filed Sept. 27, 19:59

ATTOR N EYS Patented Jan. 21, 1941 BAI'ENT QE' 3 54,? SAW TESTING DEVICE John A. Brantley, Texarkalnafkrkj assignor of seventy-five per cent Texarkana, Tex.

to Macon Luettay J arvis,

Application September 27, 1939, Serial No. 296,859 Q I z d laiu'is. (Ci.3 s zi02j" This invention relates to improvements indevices for-testing saws especially for determining the pitch of teeth in a saw of the type used in cotton gin for picking lint'from cottonbolls. l

By the expression pitch as used-in this specification and in the claims subjoined thereto is meant the angle determined by thelead face angles commonly are measured. i

It is-an object of the present invention to provide a rugged structurally-simple device for measwing with facility and accuracy the pitch of saw teeth; the device constituting-an improvement upon existing types of saw testing devices in that it-includes motion magnifying means whereby small-variations in pitch of the saw teeth being tested are disclosed by relatively large variations in reading of display means coupled to the device,

An a-dvantageof the novel device according to thepresentinvention is that itincludes no resilient'acting members and hence the deviceis not subject to being rendered inoperative by fatigue and breakdown of springs and the like as is the case with similar devicesnow in use.

A feature of the novel testing device according tothe present invention is the ease-with which-it can be used in examining relatively large numbers of teethin shortperiods oftimegor; in otherwords, it maybe-said that the-device while functioning with accuracy isnevertheless suited torapid-testingp i Y Another feature of the device according to this invention important from the-standpoint of manufacturing the same is that the elements thereof may be formed by relatively simple mechanical operations or'transactions on automatic machinery with the result that the advantages of mass production can be substantially fully realized with're'sultant lowering of thecost of the device. The structural ruggedness of the device also tends o to minimize likelihood of need of repair under conditions of normal use;

' Other objects, advantages and features of the new and improved saw testing device according to the present invention will be apparent to those skilled in this art during the course of the following description.

Regarded in certain of its broader aspects the novel saw testing device according to the present invention comprises a first member adapted to be in position upon the points of saw teeth and, movalso is adapted upon occasion to-rest aroundthe edge of- -the saw- 13 for purposes of supporting.

' The opposite end M of the frame II is provided ably mounted upon said first member, a second member adapted to rest against .an edge of :one of the saw teeth togetherrwith' moving display means'operated 'by relative m'otionrof saidimember 1 m: :1: .1 iii v. 1' .t

In order to facilitate a fuller and more complete understanding cf the presentinventiorra specific embodiment thereof herein illustrated will: be hereinafter described, it being clearly: understood, however; that the illustratedembodimentmal- 10 though" presently "preferred, is provided 'solely by way of example of the practice-of this invention and not byway of limitation thereof except insofar as the inventionis recited in the subjoined laim .1:. "2111. axes t. 15 Referring then to the drawing, Figure l is substantially a sideelevational view of the presentlypreferred embodiment offitheinstan-t invention showing same in testing position upon a fragment- 0f a circular-saw,- parts of the casingof the device being removed to expose in- I t'erior-structure, 1 l i V 1i 7 1 liig; 2 is essentially an end elevational view of the device shown in Fig; 1,

1.. FisK-S substantially a, top plan view of'the device shown in the foregoing figures;

Fig. 4f is'substantially a horizontal sectional view of Fig. l taken along'the lined-4 thereof, Fig'. 5 is substantially a side elevational view Oran auxiliary testing tlevic r EigJB is an endview of the same.

Referri'ngn'ow especially to Figs. 1 to 4 inclusive, it will be noted that thenovel testing device according to the present invention generally-designated by the numeral It comprisesa frame-ll 5 provided with a channeled end portion [2 formed byturning over parts of theframe, which is suited to receive and rest upon -the tipsof'th'e teeth A of i the" blade -B.- A An overturned' -lug-lfi the device; The lug also serves at holding the device in" alignmentupon the saw blade during testing as -hereinafterm0re-clearly will be app ent I l 7 l; with overturned marginal portions l5 defining --a chamber or casing wherein display mechanism is mounted as will be hereinafter described. A bell crank lever l6 mounted on the pin I! is provided with an extending tooth engaging member 16a formed integral with the lever arm and located beneath the pivotal mounting thereof. It is to be noted that a tooth engaging portion lBa of the lever arm includes a substantially flat surface adapted to rest against the face of one of the saw teeth being so positionable by motion of the bell crank lever. Motion of the bell crank lever is facilitated by the outwardly extending arm I61) thereof which projects somewhat beyond the frame I I, serving as a counterweight.

One end I60 of the bell crank lever is bifurcated to receive and engage with the pin 20a mounted on the pointer arm 20, the last mentioned being pivotally mounted on the supporting pin 2| attached to parts of the casing. The arm 20 is looped laterally as indicated by the reference character 2110 around portions of the arcuate dust stop 22 mounted on side portions of the casing and the end portion 20d of the arm 20 which projects outwardly through the opening lfia in the casing I5 is bent against the casing side and provided with a pointed end for facilitating comparison of a scale upon the casing side read in relation to the end 2011 of the pointer arm 20. It will be obvious that the purpose of the arcuate member 22 is to inhibit the passage of dust and the like through the opening I5a onto the moving parts of the mechanism. A weighted curved arm 20b integrally formed with the pointer arm 2|] is provided to read the pointer at rest position, that is to say to move the index to zero reading on the scale.

It is believed that it will be obvious from consideration of the drawing, especially Figs. 1 and 4, that the connector arm l8 serves to magnify motion of the bell crank lever l6, that is to say, relatively minor motion of the bell crank lever will result in relatively major motion of the outer end of the pointer arm 20.

The device according to the present invention includes an auxiliary testing unit for checking teeth outlines of saws being tested, this device being mounted upon the rear of the frame H and being designated by the reference character 40.

Referring especially to Figs. 5 and 6 wherein details of the auxiliary testing device best are illus- .plate 40 and the lip 40b is internally carefully formed to define a recess 40c corresponding in .cross sectional outline to the preferred outline of saw teeth being tested.

The device is used as follows: The overturned portion I2 of the framework II and the lug l3 are positioned upon peripheral parts of the saw and by manipulation of the lever arm I B, preferably by moving the end portion l6b thereof, the tooth engaging portion lfia of the lever arm ismoved into the position illustrated in Fig. 1 whereby the flat edge of said portion of the arm rests against the flat side of the saw tooth. When so positioned the relation of the pointer end 20d to the scale carried upon the casing I5 is noted. The scale of course is calibrated by testing of standard saws whereby variations from standard can be determined by application of the device. It is important of course that the fiat surface of the tooth engaging portion I6a of the lever arm l'6 rests firmly and exactly against the fiat edge of the tooth, but experience indicates that in operation of the device this condition easily is attained.

In testing the tooth outline a portion of the saw is positioned between the body of the plate 40 for the overturned lip 40b thereof, and as the device is moved along the saw the edges of the teeth are examined through the opening 40d to determine whether or not they conform with the standard contour defined by the recesses between the plate and lip as above described.

Experience indicates that especially in cotton gins and the like are the testing of tooth pitch and tooth outline important inasmuch as small variations in the same frequently are reflected in large variations in gin output. For these reasons then the testing apparatus according to the present invention has especial application to use in testing devices of this character because both of the facility with which the tests may be conducted and also the accuracy of the measurements obtained.

It is to be understood of course that this invention is capable of extended application and is not confined to the precise illustrated forms nor described construction and, therefore, such changes and modifications may be made therein as do not afiect the spirit of the invention nor exceed the scope of the appended claims.

Having thus described the present invention, what it is desired to secure by Letters Patent is:

l. A device for testing circular saws comprising a frame having a channeled portion for resting upon edge parts of a saw; a swinging arm pivoted to said frame, a transversely extending lug on said arm having a fiat side portion adapted to rest between two saw teeth and against an edge of one of said teeth whereby the position of said arm relative to said frame is related to the pitch of the saw tooth against which said lug rests; a scale carried on said frame; a pivotally mounted index sweeping said scale; and means coupling said index and said arm whereby the position of the index relative to the scale is related to the pitch of the saw being tested.

2. A device for testing circular saws comprising a frame having a channeled portion for receiving and resting tangentially upon peripheral edge parts of a saw; a swinging arm pivoted to said frame, a transversely extending lug on said arm having a fiat side portion adapted to rest between two saw teeth and against an edge of one of said teeth whereby the position of said arm relative to said frame is related to the pitch of the saw tooth against which said lug res s; a scale carried on said frame; a pivotally mo ted index sweeping said scale;- and means cou ling said index and said arm whereby the positi n of the index relative to the scale is related to the pitch of the saw being tested.

- JOHN A. BRANTLEY. 

